This section provides background information related to the present disclosure which is not necessarily prior art.
According to the data from WORLD HEALTH ORGANIZATION, an agency of the United Nations, worldwide obesity has increased over 200% since 1980, and in US 68% of the population is considered to be overweight or obese (i.e. Body Mass Index greater than 25). It has been proven that obesity has causal relationship with a number of diseases such as coronary heart disease, type-2 diabetes, and various types of cancers (e.g. endometrial, breast and colon). With such findings, obesity control and management became an important medical, social, and policy issues in recent years. Two important components of obesity management are diet control and physical exercise.
Traditionally, researchers and health practitioners have used self-reported questionnaires for estimating both food intake and physical activity levels for high-risk individuals. In recent years, accelerometry-based instrumentation techniques are starting to emerge as alternatives to questionnaires for physical monitoring. For food intake monitoring, however, not many instrumented efforts were reported in the literature.
In most questionnaire based studies, participants have shown a tendency of intentionally or unintentionally underreporting the amount of their food intake. Additionally, data self-reported by elderly people are often unreliable since amnesia is quite common among that population. It was also found that women are more likely to underreport their fat consumption while over-report their protein intake. It was experimentally shown that due to the above and other similar reasons, questionnaire based self-reporting systems are often too unreliable to be successfully used towards food intake monitoring for obesity management. An instrumented system, if available, could eliminate such subjectivity attached to questionnaire based systems.
Current solutions can be divided into two categories, invasive and non-invasive. Invasive methods, such as videofluoroscopy and functional magnetic resonance imaging (fMRI), cannot be used for everyday monitoring and dietary analysis. Many of the non-invasive methods use surface electromyography (SEMG) or movement sensors to measure the movement of larynx and the activity of the muscles associated with the swallow event. But these sensors are put at the neck, which would lead to the reluctance of the subjects to wear them. Some use Respiratory Inductance Plethysmography (RIP) to measure the movement of the chest, but these devices are quite expensive and are driven by other modules thus not suitable for wearable solutions.